Dynamic Host Configuration Protocol.

Local Area Network. A network that typically includes computers which are physically close, such as in one office, usually connected with hubs and switches rather than routers.

Network Interface Card. A.k.a. network card, or Ethernet card.

Network Address Translation. A technique whereby IP traffic from multiple IP addresses behind a firewall are made to look to the outside as if they all come from a single public IP address.

See Also Wikipedia Network Address Translation page .

Wide Area Network. A network that spans a large area, typically including routers, gateways, and many different IP networks.

In the context of firewalls, the WAN interface is the one directly connected to the Internet.